This invention relates generally to a container and, more particularly, to a container for shipping and storing radioactive materials.
In view of the many hazards and problems associated with the management of radioactive materials, numerous Federal Regulations have been promulgated governing the handling of such materials. Regulations controlling the transport and storage of radioactive materials have been established to prevent the loss or dispersal of material during shipment and to ensure the safety of the public as well as the transportation workers involved. Basically, such materials must be transported in packages or containers which shall prevent loss or dispersal of the contents, retain shielding efficiency, assure nuclear criticality safety, and provide adequate heat dissipation under both normal transport and hypothetical accident conditions.
Many fuel storage and shipping containers, conforming to the requirements of the Regulations, have been developed to safely transport radioactive materials. While such containers admirably serve the purpose for which they were designed, they possess certain disadvantages. For example, these containers generally include an inner, central canister defining a cavity for containing the radioactive material, an annular radiation shielding filler surrounding the canister and which usually occupies substantially more space than the radioactive material, an outer shell encapsulating the layer of nuclear shielding, and heat rejecting fins projecting outwardly from the outer shell. Thus, the overall package occupies a substantially large volume compared to the relatively small volume of the contained radioactive material, resulting in a huge package for housing a relatively small, and thereby expensive and inefficient, payload.
Also, the thermal transfer of heat generated by the radioactive material poses problems, especially with the pressure seals employed to provide an airtight containment. It has been found that conventional seals, usually formed of polyvinyl chloride or polyethylene, deteriorate at about 250.degree. F. and are rendered ineffective. Thus, the seal temperatures dictate the upper temperature limitations permissible within the container. Another disadvantage with conventional containers is that they are not always compatible with remote handling apparatus, nor with the more recently developed automated processes employed in the fabrication of nuclear fuels.
Accordingly, it is a primary object of the present invention to obviate the above noted shortcomings by providing a new and improved shipping container for housing a plurality of canister assemblies containing radioactive material in an optimum payload configuration or package.
It is another object of this invention to provide a container for shipping or storing radioactive material in conformance with present day Federal Regulations.
It is still another object of the present invention to provide the foregoing container with a heat transfer arrangement maintaining the internal temperatures of the container well within tolerable levels.
It is a further object of this invention to provide a shipping container especially compatible with automated remote handling means.
These and other objects, advantages, and characterizing features of the present invention will become clearly apparent from the ensuing detailed description of an illustrative embodiment thereof, taken together with the accompanying drawings wherein like reference characters denote like parts throughout the various views.